This invention relates to standpipes which are mounted to coke ovens to remove coke oven gases generated during the coking process. More particularly, the invention relates to leakages of gas from a capped opening in the standpipe.
In the coking process, coal is deposited in a coke oven, wherein the coal is baked in a closed environment. By-product volatile substances are produced during the coking process. The by-products are primarily in a gaseous state permeated with particulate matter. The by-products are drawn from a coke oven through a standpipe which is mounted to the top of the coke oven in communication with the oven interior via an oven opening. The standpipe is also in direct communication with a gas collection main wherefrom by-product gases are collected and transported for processing.
Conventionally, standpipes are comprised of a refractory-lined ascension pipe with a gooseneck pipe extension thereto attached. The standpipe is mounted vertically atop a coke oven, the gooseneck portion affixed to a gas collection main. Because the by-product gases carry particulate material, there is a propensity for the particulate material to collect and consolidate in a portion of the gooseneck pipe which, if left unchecked, would obstruct passage through the standpipe. To facilitate the removal of any consolidated material from the interior of the gooseneck pipe, an opening is strategically located in the gooseneck pipe wherethrough one can periodically clean and dislodge any consolidated material therein.
Customarily, a metal standpipe cap encloses the opening in the gooseneck portion of the standpipe during normal operation. The cap is in direct metal-to-metal contact with the rim of the opening, which creates the opportunity for by-product gases to seep from the standpipe between the cap and rim interface. The leaking gas creates an environmentally adverse condition. Conventional soft sealing means cannot be deployed to alleviate standpipe leakage due to the extreme temperature present in the vicinity of the standpipe opening (1500.degree. to 1800.degree. F.) which would destroy conventional soft sealing means.
The present invention provides a means to eliminate standpipe cap leakage.